More Streams

- Added unrelated things

MoreStreams/MoreStreams/src/main/java/ocp/practice/basics/MoreStreams/App.java

@@ -1,8 +1,14 @@
 package ocp.practice.basics.MoreStreams;
 
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 /**
@@ -11,7 +17,7 @@ import java.util.stream.Stream;
  */
 public class App 
 {
-    public static void main( String[] args )
+    public static void main( String[] args ) throws IOException
     {
         // Practice dirtying streams
 //    	practiceDirtyLinkage();
@@ -23,10 +29,88 @@ public class App
 //    	reductionExamples();
     	
     	// Stream operations (findFirst, anyMatch, allMatch)
-    	matchingExamples();
+//    	matchingExamples();
     	
     	// Flat mapping
-    	flatMapping();
+//    	flatMapping();
+    	
+    	// More complicated grouping by
+    	groupingByWithMapping();
+    }
+    
+    /**
+     * Here we look at using grouping by
+     * but in a more complicated manner
+     * 
+     * This is cascading collectors
+     * @throws IOException 
+     */
+    private static void groupingByWithMapping() throws IOException
+    {
+    	List<String> names = List.of("Tristan", "Thomas", "Abigail", "Andy");
+    	
+    	Map<Character, List<Integer>> map = names.stream()
+    	.collect(Collectors.groupingBy(App::getFirstLetter,
+    			Collectors.mapping(App::getCharValue, Collectors.toList())
+    			
+    			));
+    	
+    	System.out.println(map);
+    	
+    	/**
+    	 * The {@link Collectors#toMap} method will raise
+    	 * an exception if the duplicate key, from the key
+    	 * mapper function, maps to an existing key.
+    	 * 
+    	 * Therefore we provide it with a BinaryOperator
+    	 * which is called in such occasions and is passed
+    	 * the present key-value and the incoming one,
+    	 * combines them are stores that at the key's
+    	 * value
+    	 */
+    	names = List.of("Tristan", "Thomas", "Abigail", "Andy");
+    	System.out.println(names.stream().collect(Collectors.toMap(App::getFirstLetter, i->i, (i,x)->i+x)));
+    	
+    	
+    	var things = new ArrayList<String>();
+    	testMethod(things);
+    	
+    	Path p1 = Path.of("/");
+    	Path p2 = Path.of("/././dev2");
+    	
+    	System.out.println("IsSameFile?: "+Files.isSameFile(p1, p2));
+    	
+    	
+    	int i1 = 1;
+    	double i2 = i1;
+    	Double i3 = i2;
+
+    	Integer i4 = 1;
+    	i3 = (double)i4;
+    	
+    	i2=i4;
+    	
+//    	i3=2;
+//    	i4 = 2.0;
+ 
+    }
+    
+    private static void testMethod(List<String>... listOfLists)
+    {
+    	for(List<String> d: listOfLists)
+    	{
+//    		d.get(0);
+    	}
+    }
+    
+    private static int getCharValue(String name)
+    {
+    	return name.length();
+    }
+    
+    private static char getFirstLetter(String name)
+    {
+    	return name.charAt(0);
     }
     
     /**

OOP/even_more_oop/EvenMoreOOP/.gitignore

@@ -0,0 +1 @@
+/target/

OOP/even_more_oop/EvenMoreOOP/pom.xml

@@ -0,0 +1,81 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>ocp.oop</groupId>
+  <artifactId>EvenMoreOOP</artifactId>
+  <version>0.0.1-SNAPSHOT</version>
+
+  <name>EvenMoreOOP</name>
+  <description>A simple EvenMoreOOP.</description>
+  <!-- FIXME change it to the project's website -->
+  <url>http://www.example.com</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.source>1.7</maven.compiler.source>
+    <maven.compiler.target>1.7</maven.compiler.target>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>3.8.1</version>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
+      <plugins>
+        <plugin>
+          <artifactId>maven-clean-plugin</artifactId>
+          <version>3.1.0</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-site-plugin</artifactId>
+          <version>3.7.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-project-info-reports-plugin</artifactId>
+          <version>3.0.0</version>
+        </plugin>
+        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
+        <plugin>
+          <artifactId>maven-resources-plugin</artifactId>
+          <version>3.0.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-compiler-plugin</artifactId>
+          <version>3.8.0</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-surefire-plugin</artifactId>
+          <version>2.22.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-jar-plugin</artifactId>
+          <version>3.0.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-install-plugin</artifactId>
+          <version>2.5.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-deploy-plugin</artifactId>
+          <version>2.8.2</version>
+        </plugin>
+      </plugins>
+    </pluginManagement>
+  </build>
+
+  <reporting>
+    <plugins>
+      <plugin>
+        <artifactId>maven-project-info-reports-plugin</artifactId>
+      </plugin>
+    </plugins>
+  </reporting>
+</project>

OOP/even_more_oop/EvenMoreOOP/src/main/java/ocp/oop/EvenMoreOOP/App.java

@@ -0,0 +1,38 @@
+package ocp.oop.EvenMoreOOP;
+
+/**
+ * Just testing some things out
+ *
+ */
+public class App 
+{
+	public class A
+	{
+		
+	}
+	
+	public static class B
+	{
+		
+	}
+	
+    public static void main(String[] args)
+    {
+        class C
+        {
+        	
+        };
+        
+        App app = new App();
+        
+        // Non-static class must be accessed via a nn-static way (object instance)
+        app.new A();
+        new App().new A();
+        
+        // B MUST (not "can") as a static instance explicit top-class or not
+        new App.B();
+//        app.new B();
+        new B();
+        new C();
+    }
+}

OOP/even_more_oop/EvenMoreOOP/src/site/site.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<project name="EvenMoreOOP" xmlns="http://maven.apache.org/DECORATION/1.8.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/DECORATION/1.8.0 http://maven.apache.org/xsd/decoration-1.8.0.xsd">
+  <bannerLeft>
+    <name>EvenMoreOOP</name>
+    <src>https://maven.apache.org/images/apache-maven-project.png</src>
+    <href>https://www.apache.org/</href>
+  </bannerLeft>
+
+  <bannerRight>
+    <src>https://maven.apache.org/images/maven-logo-black-on-white.png</src>
+    <href>https://maven.apache.org/</href>
+  </bannerRight>
+
+  <skin>
+    <groupId>org.apache.maven.skins</groupId>
+    <artifactId>maven-fluido-skin</artifactId>
+    <version>1.7</version>
+  </skin>
+
+  <body>
+    <menu ref="parent" />
+    <menu ref="reports" />
+  </body>
+</project>

OOP/even_more_oop/EvenMoreOOP/src/test/java/ocp/oop/EvenMoreOOP/AppTest.java

@@ -0,0 +1,38 @@
+package ocp.oop.EvenMoreOOP;
+
+import junit.framework.Test;
+import junit.framework.TestCase;
+import junit.framework.TestSuite;
+
+/**
+ * Unit test for simple App.
+ */
+public class AppTest 
+    extends TestCase
+{
+    /**
+     * Create the test case
+     *
+     * @param testName name of the test case
+     */
+    public AppTest( String testName )
+    {
+        super( testName );
+    }
+
+    /**
+     * @return the suite of tests being tested
+     */
+    public static Test suite()
+    {
+        return new TestSuite( AppTest.class );
+    }
+
+    /**
+     * Rigourous Test :-)
+     */
+    public void testApp()
+    {
+        assertTrue( true );
+    }
+}